Reversible Color Switching of an Organic Crystal Induced by Organic Solvent Vapors

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• 作者：Kotaro Fujii ; Aya Sakon ; Akiko Sekine ; Hidehiro Uekusa
• 刊名：Crystal Growth & Design
• 出版年：2011
• 出版时间：October 5, 2011
• 年：2011
• 卷：11
• 期：10
• 页码：4305-4308
• 全文大小：773K
• 年卷期：v.11,no.10(October 5, 2011)
• ISSN：1528-7505

文摘

5-Aminoisophthalic acid (AIPA) was found to undergo reversible color change on exposure to solvent vapors, which is called vapochromism, via pseudopolymorphic transformations between the pale-pink hemihydrate and the yellow anhydrous crystals. By exposing methanol, ethanol, or acetonitrile vapor on the hemihydrate crystal, the hemihydrate crystal transformed into a novel anhydrous crystal and the anhydrous crystal returned into the hemihydrate crystal under the existence of water vapor. X-ray structural analysis revealed that the AIPA molecule is in a zwitterionic form in the hemihydrate crystal whereas it is in a nonionic form in the anhydrous phase. Theoretical calculations revealed that the isomerization between nonionic and zwitterionic forms causes a solid-state color difference.